In U.S. patent application Ser. No. 10/266,677 filed Oct. 9, 2002 (WO 03/030652), assigned to the assignee hereof and the disclosure of which is incorporated herein by reference, there is described the preparation of a flax protein isolate. As set forth therein, there is provided a flax oil seed protein isolate having a protein content of at least about 90 wt %, preferably at least about 100 wt %, as determined by Kjeldahl nitrogen×6.25 (N×6.25) on a dry weight basis.
In such process, yields of flax protein isolate were limited because of the inability to concentrate the protein solution to high protein contents owing to the presence of water-soluble mucilage. Flax seed mucilage is a gummy substance consisting substantially of polysaccharides. The presence of the mucilage in protein products separated from flax oil seed meal by other processes makes it difficult to produce products with protein contents high enough to be classified as isolates.
Flax seed is known to contain about 34 to about 37 wt % proteins and several different protein components, distinguished by different sedimentation coefficients (S), have been identified. These proteins include a 12S globulin, known as linin, and 2S albumin, known as colinin.
Linola® oil seed, distributed by Agricore United, is a mutant of flax oil seed in which the fatty acid composition has been changed and linolenic acid (C18:3) has been substantially reduced from about 50% in conventional flax oil seed to about 2%, through traditional breeding procedures. These modifications were made to provide, from the resulting Linola oil seed, an edible polyunsaturated oil substantially similar to sunflower oil in fatty acid composition.